Shell Dissolves in Seawater

Preview A shell placed in seawater with increased acidity slowly dissolves over 45 days.
(Courtesy of David Littschwager/National Geographic Society)

Over a 10-year period, NOAA scientists have collected 72,000 seawater samples, and their data show that the ocean is becoming more acidic because of climate change. That small change in acidity is enough to dissolve the shells of animals like this pteropod. In the lab, its shell dissolved in high-acidity seawater in 45 days. And in the wild, pteropod shells have already started dissolving in the Southern Ocean. Find out more about ocean acidification and its effects on different organisms.